Foundry sand cooler



July 8, 1952 H. DOK 2,602,242

FOUNDRY SAND COOLER Filed Nov. 21, 1949 30 I; figo 20 3.?

- IN V EN TOR. 15. 4212) Doz firraewsy- Patented July 8, 1952 2 2,602,242 FQ-UNDRY' SAND COOLER Harry 'D0k, Burbank, Calif., 'assignor to Los Angeles Steel Casting 00., L Angeles, Calif., a corporation of California Application November 21, 1949, Serial No. 128,539

This invention relates to an improved apparatus for cooling molding sand'or foundry sand and other granulated material. Sand molds used in foundry practice for the purpose of casting various metals are usually composed of-carefully preselected sand particles which have been processed so that they are clean, have a selectedproportion of fines and a minimum of foreign residues, a desired grain structure and have been bonded'together by means of soluble, gummy carbohydrates, such as dex trin or other glutinous material. It is economically desirable to reclaim and re-use the sand in such molds because of an appreciable saving in'shipping, testi g, and storing-of sand.

In normal foundry practice, the same sandmay be used several times in one day for casting purposes. Since the re-used sand must be carefully processed and handled'so that the sand molds made therefrom will have the desired and necessary refractoriness, strength and permeability, a quick, effective and satisfactory method of processirig and cooling used sand is essential in order to repeatedly place it in proper condition'ior reuse. Foundry sand'from the molds is ata temperature of well over the boiling point of water, say temperatures on the order of 230- 60"F. and since during casting many of the soluble bonding materials have-been carbonized, it is necessaryto re-mix the sand with new bonding agents in order to produce the desired porosity, strength and permeability in the sand. It is not possible to introduce these bonding agents into a hot sand since this tends to produce steaming which drives off the bonding agents and makes it impossible to control the quantity of bonding agent remaining in the sand. Furthermore, before the sand is re-used, it is necessary to remove a large proportion at least of the carbonizedmaterial which is in the form of ex-* tremely fine particles. The presence of these excessive fines would impair the permeability and other desired characteristics of the sand. This invention is directed primarily to apparatus which is capable of quickly, efiectively and accurately cooling and cleaning used molding sand so that it maybe introduced into a rolling mill or. muller at a desired, relatively cool temperature.

An object of this invention is to design and provide an apparatus for cooling and cleaning used molding sand whereby the cleaning and cooling operation is substantially a continuous process so that sand may be quickly reclaimed and re-used.

4 Claims. (01-34-47) Another object of this invention is to provide an apparatus employing a high velocity air stream for the purpose of breaking up conglomerates'or particles, removing'excessivefines and cooling individual sand grains to a desired temperature below 200 F. whereupon the sand is in condition for re-use. .s I

Still another object of this invention is to designand provide an apparatus-for cooling and cleaning used-molding sand wherein the amount of. fines and residues in cooled sand are readily controlled. a v a Ge nerally speakingfthis invention contem: plates the provision of two vertically spaced, axially aligned cylinders connected by a narrow throat, an upwardly directed stream of air passingthrough said cylinder-sand through the throat with high velocity means for introducing sand particles into the; upper cylinder for agitation therein, whereby conglomerate particles of sand are separated into individual sand grainasaid sand falling through the narrowthroat where the upwardly directed high velocity air stream effectively cools each individualsand grain, the cooled sand falling through the bottom cylinder upon an inclined annular surface surrounding an air inlet for flowing by gravity to a discharge outlet. Sand flowing from the discharge outlet may then be. transported to a muller or to storage by any convenient means. The proportion of fines and residues carried by the air stream out of the top of the upper cylinder is controlled by a regulatable damper or valve mounted in a top air outlet communicating with a dust separator.

Other objects and advantages of this invention will be readily apparent from the following description of the drawings.

In the drawings:

Fig. l is a schematic view illustrating the use of a cooler embodying this invention in a process for reclaiming foundry sand. I

Fig. 2 is a side elevation of a cooler embodying this invention, the side elevation being partly in section, the plane of the section being taken in a vertical transverse plane passing through the axis of the cooler.

Fig. 3 is a fragmentary side view of the cooler shown in Fig. 2, the view being taken in the plane indicated by the line IIIIII of Fig. 2.

Fig. 4 is a fragmentary side elevation of the cooler shown infFig. 2, the view being taken from the plane indicated by the line IV-'IV of Fig. 2.

Fig. 5 isa sectional view taken in a plane transverse to the axis of the cooler as indicated by line VV of Fig. 2.

still held together by the bonding agent used in preparation of the sand mold) as well as carbonized residues of bonding agents.

terior of such a conglomerate sand particle re,-

tains its heat until the grains are separated;

During the above handling of the foundry sand temperature reduction of the sand. particles. especially the interior thereof is not materially reduced. Hot sand may be introduced to a cooler embodying this invention at a temperature ofabout 225-250 F. The cooler preferably reduces the temperature of the sand particles to .150*-170 F., at which temperature the sand is suitable for introduction into a mixer for mixing with other sand and a bonding agent in preparation for use in sand molds. 1

The cooler generally indicated at. Ill comprises 2 a ;vertical, -.axially aligned assemblage including may be approximately the same. The. neck I5 may be joined with they lower cylinderby a horizont'aLannular wall l land with the upper ,cylim der by means of ,a diagonally disposed upwardly directedrannula'r-wall 18.

Joined to the lower annular edge of the bottom cylinder 'j'II may bean inwardly and downwardy inclined annular wall I9. Connected to the inner circumferential edge of wall I9 may be avertically depending truncated cylinder 20, the truncation of said cylinder being in an inclined plane including an element of wall I9 disposed diametrically opposite the vertical dimension of truncated cylinder 20 of greatest length.

An inclined annular bottomwall 2| lies in said inclined plane and is suitably joined to said truncated cylinder. Adjacent the low point of said wall 2! and. in the portion of the truncated cylinder of greatest depth, may be provided a rectangular outlet 22 for discharge of cooled sand collected on inclined annular wall 2 I. The angle of inclination of said wall 2| may be suffic ient to produce rapid gravitational flow of sand from the surface of said wall through outlet 22.

Extending upwardly through the inclined wall 2I may be a generally cylindrical air duct 23 having a diameter less than the diameterof the truncated cylinder 20 so as to provide an annular space or recess 24 surrounding the upstanding air duct 23. The top 25 of duct 23 may project upwardly beyond the line of juncture of the diagonal wall I9 and the truncated cylinder.

The lower end of air duct 23 may be suitably tapered at 23 so as to provide an inwardly flaring funneL'and the lower edge of said funnel may communicate with a suitable T 27 provided with an'airintake duct 28 disposed at right angles to the axis of the funnel 23. The interior of the T may be provided with a plurality of transverse, upwardly curved louvers 30 arranged in parallel relation and lying in a planar zone inclined to the direction of air flow for directing a current of air upwardly through the funnel and through the air duct 23. The louvers 39 may be mounted in a suitable frame secured within the T or may be welded directly to thf T, {irrselected arrange-.

ment. At the bo'ttomof 'the T" -2'I 'and axially aligned with the funnel 26 may be provided an inwardly flared discharge duct 3| for the purpose of collecting a few particles of sand which may fall through the air duct 23. A suitable discharg'e'valve 32=may be provided at the bottom of the dischargeduct 3! in order to permit periodic 'cleaiiing ofsand particles from duct 3|. The airintakeJB-may be suitably connected by means of ducts to any suitable air-blowing apparatus such as is generally indicated at 33 in Fig. 1.

The upper cylinder I3 is provided with a diagonal, downwardly directed, hot sand chute 34 communicating withohamber I4 at a point above throat It and below the. top of cylinder I3 for permitting sand particles which have been processed-v through the grizzly, hammer mill, and screentofflow by gravity through the hot sand intake port 35 into. said chamber I4.

Adjacent the topof cylinder I3 and at oneside thereof is provided an, air outlet port 36 connected to aduct 31' which extends to'the inlet side of'a suitable icyclone dust collector generally indicated atv 38. of anywell known make and manufacture; In duct 31 may be provided a butterfly-type damper ;39 which may be selectively adjusted to gcontrol'the quantity of fines and carbonaceousl residues carried by the upwardly directed current of air into'the discharge duct 31. IllEWlll, be also apparent that damper 39 regulates the r air pressure created within the cooling assemblage. I

In .operation after; sand has been processed through the grizzly,.hammei* mill,'and screening operations; j-the airj blower 33 maybe "started to providexa current of upwardly directed ;air through the air duct 23 and through the bottom chamber, throatiandupper chamber of the cooling-assemblage." Since the bottom chamberv I2 has a greater dimension, than the throat, I6, air pressure is built up in chamber I2 in order to provide; an air stream'of high velocity through the throat l6. Hot sand introduced into the upper chamber [4 through the intake port 35 is picked up by said air stream and held in suspension in the upper chamber for a short period of time; As a result of the high velocity of the air stream leaving throat I6, the air in chamber I4 is provided a turbulent action which tends to break up conglomerate particles of sand so that the sand becomes finely divided into individual grains of sand. The agitation of the sand particles in suspension in the upper chamber'also separates' fines and residues from the sand which are carried upwardly and'into the air discharge duct 31.

The individual grains of sand,'after being held in.;su'spension for a short time, fall by gravity through the throat I6 where each individual grain is subjected to cooling action of the high velocity air stream. Since the lower chamber I2 is of greater diameter than the throat I6, as the fallingparticles of sand enter chamber I2 they tend to 'move adjacent the outer circumferential margins'of the chamber I2 and fall upon the diagonal'wall l9 and thus are collected on the t ansverse diagonal wall 2! in the annular space 24 between air duct 23 andtruncated cylinder 20. The cooled sand particles are discharged by gravitythrough the cooled sand outlet and may be discharged into any suitable .conveying mea'ns for carrying the sand to themuller for re-mixing the cooledsand with a quantity of new sandand glutinous'm'aterial in preparation-for new molding sand; As illustrated a conveyor belt isshov'vn disposed beneath the cooled sand outlet for conveying said sand to a'suitablepoint.

It should be particularly noted that the-$11K, bulent action of the air iin the upper-"cylinder tends to massage and rub the individual particles of sand so as to remove any fines and residues carried into the upper cylinder through the hot sand intake. These fines and residues are discharged into the cyclone where they may be separated from the air stream and relatively During operation of the cooler the cooler, are rapidly cooled by action of the air stream of high velocity passing through throat l6, and are rapidly removed from the cooler by continuous flow of sand from the inclined wall 2! through thesand outlet 22. claimed sand may then be preferably transported to a muller for mixing with other sand in preparation for molding.

All changes and modifications coming within the scope of the appended claims are embraced thereby.

I claim:

1. In a foundry sand cooler, the combination of: an upper vertically disposed cylindrical member providing an upper elongated chamber adapted to receive sand to be cooled; a lower cylindrical member axially aligned with said upper member, spaced therefrom, and providing a lower chamber; said upper and lower members each being provided with a bottom inwardly inclined wall; an open ended cylindrical throat member of smaller diameter than that of said members extending between said upper and lower membersand connected to the inclined wall of the upper member; a transverse annular wall connecting the lower member to the throat member; a truncated cylindrical portion depending from the inclined wall of the lower member; a cylindrical air inlet duct concentrically positioned within said truncated cylindrical portion and coaxially aligned with said throat member, said duct being of smaller diameter than the throat member and having an upper portion extending into the lower chamber; a downwardly inclined annular wall encircling said duct and connected to the truncated cylindrical portion for defining an annular collecting chamber for cooled sand particles; a valved outlet in the upper member for controlling pressure within said chambers; an

outlet port in said truncated cylindrical portion.

for discharge of collected cooled sand; said air inlet duct providing means for introducing a high velocity stream of air therethrough and into said lower chamber for moving falling sand particles radially outwardly, through said throat member The cooled re- 6." and intosaid :upper? chamber for holding: sand particles in agitated suspension forselectedatime intervals". 5 2'; In'fa:foundrysand'cooler, the combination of ani'upper member defining an'upper chamber adapted to receive: sand to be cooled; alower member spaced from said upper member and de'-' fining la lower chamber? means connecting-said upper-rand lower members, including a' throat member providing a restricted passageway: between said chambers; s'aidlconnecting means-in eluding an annular 1 wall xlyin'g in a plane trans-# verse to. th axis of the throat member for joining the throat member to the lower member; a truncated cylindrical portion depending from said lowersmember an air. inlet yduct; of smaller: diameter than the throat member coaxially aligned therewith, positioned within said truncated portion and projecting within the lower chamber; an inclined annular wall encircling said duct and closing the lower end of the truncated portion; a

. discharge port in said truncated portion; a valved outlet in the upper member; said inlet duct being adapted to introduce 'a stream of air therethrough and into and through said lower chamber, throat member, and upper chamber, whereby sand introduced in said upper chamber may be held in agitated suspension, cooled as it falls through said throat member and displaced radially outwardly as it falls through said lower chamber.

3. In an apparatus for cooling particles of foundry sand, the combination of: a pair of vertically arranged spaced upper and lower members, each having a virtually cylindrical chamber of uniform cross-sectional area, the upper chamber being elongated and adapted toreceive hot sand introduced from the side thereof; means connecting said members and providing communication therebetweeen including a cylindrical throat member defining a passageway of less cross-sectional area than said chambers, the throat member and the lower member being joined by an annular wall lying transversely to the axis of the throat member; a depending partially cylindrical portion connected to said lower member and in communication with said lower chamber; an air inlet duct concentrically positioned within the portion and extending upwardly therefrom into said lower chamber; an inclined wall encircling said duct and connected to said portion for collecting sand falling from said lower chamber; said duct being of smaller diameter than said throat member and coaxially aligned therewith,

whereby a high velocity stream of air emitted from said air duct urges falling sand particles in the lower chamber radially outwardly for collection on said inclined wall and agitates said sand particles in the upper chamber for cooling thereof; a valved outlet on said upper chamber; and a sand outlet on the depending portion to discharge sand collected on the inclined wall.

4. In an apparatus for cooling particles of foundry sand, the combination of a pair of vertically arranged spaced upper and lower members eash having a cylindrical chamber of virtually uniform cross-sectional area, the upper chamber being adapted to receive hot sand; means connecting said members and providing communication between said chambers including a cylinrrical throat member defining a passageway of less cross-sectional area than said chambers, said throat member and lower member being connected by an annular transverse wall lying in a plane perpendicular to the axis of the throat member; a depending cylindrical portion of less diameter than said lower member connected thereto and in communication with said lower chamber; an air inlet duct concentrically positioned within the depending portion and projecting'upwardly into said lower chamber; an inclined'wall encircling-said duct and connected tohsaidportion for defining a sand collecting chamber; said duct being of smaller diameter thansaid throat member and coaxially-aligned therewith; a valved outlet on said upper chamberya'nd a sandoutlet on the depending portion.

-1" HAR.-RYDOK.-

- REFERENCES CITED Number Number v 463,060

8. UNITED STATES PATENTS Name Date Cady Nov. 21, 1916 Dow June 19, 1923 Neuman et a1 June 6, 1933 Voskamp Apr. 13,1937 Bowen Nov. 30, 1943 Belchetz et a1. 1 May 1,1945 FOREIGN PATENTS Country 1 7 Date Great Britain Mar. 22, 1937 

